Apparatus for making nonwoven fabrics

ABSTRACT

APPARATUS FOR THE CONTINUOUS PRODUCTION OF NONWOVEN FABRIC WHICH INCORPORATES A SUPPORTED, CONTINUOUS BELT TYPE FEEDER AND DRIVE MECHANISM FOR ADVANCING A PLURALITY OF WRAP STANDS ALONG A HORIZONTAL PATH IN A LONGITUDINAL DIRECTION, WITH A DANCER ROLL MECHANISM INCORPORATED THEREIN FOR TENSION CNTROL THEREOF, AND A FILL STAND APPLYING DEVICE DISPOSED FOR ROTATION ABOUT THE WARP STRANDS AS THE WARP STRANDS ARE MOVED ALONG THE FEEDER MECHANISM.   D R A W I N G

M 30, 1971 BASCOM ET AL 3,573,137

APPARATUS FOR MAKING NONWOVEN FABRICS Original Filed 001:. 31, 1966 4Sheets-Sheet 1 a-n-n-vx-q-e-u-ami Wk HULL/1% H. @4560! JON/V J GREG/Mmmh 30, 1.971 BASCQM ET AL 3,573,137

APPARATUS FOR MAKING NONWOVEN FABRICS Original Filed Oct. 51, 1966 4Sheets-Sheet 2 52 J'l'l'g. 8., n5 0 9. v

U .fw 66 3 L A m M O C S A B a H APPARATUS FOR MAKING NONWOVEN FABRICSOriginal Filed Oct. 31, 1966 4 Sheets-Sheet 3 HULL/5' N. 845606! JON/VJ- 51750] U 371 BASQQM ET AL 3,573,137

APPARATUS FOR MAKING NONWOVEN FABRICS Original Filed Oct. 31. 1966 4Sheets-Sheet 4 HOLLIS H. BASCOM JOHN J. GRECI United States Patent3,573,137 APPARATUS FOR MAKING NONWOVEN FABRICS Hollis H. Ilascom andJohn J. Greci, Livermore, Califi, assignors to Green Corporation,Livermore, Calif. Original application Oct. 31, 1966, Ser. No. 590,910.Divided and this application Apr. 16, 1969, Ser. No. 835,842

Int. Cl. 1331c 1/00, 1/08; B65h 81/00 US. Cl. 156-428 12 Claims ABSTRACTOF THE DISCLOSURE Apparatus for the continuous production of nonwovenfabric which incorporates a supported, continuous belt type feeder anddrive mechanism for advancing a plurality of warp strands along ahorizontal path in a longitudinal direction, with a dancer rollmechanism incorporated therein for tension control thereof, and a fillstrand applying device disposed for rotation about the warp strands asthe warp strands are moved along the feeder mechanism.

This is a division of application Ser. No. 590,910, filed Oct. 31, 1966.

This invention relates to nonwoven fabrics and particularly relates totechniques and apparatus for obtaining precise strand positioning withlow adhesive content in the completed fabric.

The present invention relates to improvements in the process andapparatus disclosed in the copending United States application of HollisH. Bascom, Ser. No. 281,421, filed May 20, 1963, which matured into U.S.Pat. No. 3,391,043 on July 2, 1968 and in the copending United Statesapplication of Hollis H. Bascom, John J. Greci and Richard G. Jenkins,Ser. No. 365,318, filed May 6, 1964 which matured into US. Pat. No.3,391,039 on July 2, 1968.

As described in the two above noted applications the general process towhich this invention relates is one in which a number of warp strandsare moved, under a controlled tension, along the cylindrical surface ofa stationary cylindrical support while one or more fill strands arewound about the warp strands. The fill strands are taken from threadpackages mounted on a drum which is rotatable about the cylindricalsupport and the longitudinally moving warp strands. A magazinecontaining a liquid binder is also mounted on the drum. A metering tipextends radially inwardly from each magazine and into close proximity tothe juncture of the fill strand and the warp strand. A separate magazineis provided for each fill strand, and each fill strand is guided throughits associated magazine to apply binder to the fill strand. As the fillstrand package and its associated magazine are rotated about the warpstrand the fill strand is successively engaged under tension with thewarp strand. Because the warp strands are moving horizontally, the fillstrand forms a helix on the warp strand. The tube of fabric thus formedis cut, after the binder has set, along a line parallel to the warpstrands. The fabric is then opened to a flat sheet and wound upon astorage roll.

Prior application Ser. No. 365,318 (now U.S. Pat. No. 3,391,039) notedabove, described a process improve ment in which a moving sheet wasinterposed between the warp strands and the support to keep the binderout of contact with the support to prevent build up of binder on thesupport. The sheet was separated from the fabric at the outlet end ofdrive rollers which engaged the fabric to pull the fabric along thesupport. As pointed out in application Ser. No. 365,318 (now US. Pat.No. 3,391,039) the moving sheet, in addition to keeping binder PatentedMar. 30, 1971 'ice off of the support, helped to carry low thread countmaterials and provided a certain degree of stabilization during the timethat the binder or adhesive was setting.

Maintaining the junctures between the warp and fill strands in astabilized condition during the time that the binder is drying is alwaysan important consideration in making nonwoven fabrics by the generalprocess described above. It becomes critical with fragile fabrics havingfine yarn or low thread counts. With such fabrics it has been foundnecessary to eliminate even the relatively small driving stressesintroduced to the fabric by the octagonal arrangement of drive rollsdescribed in the above noted application Ser. No. 365,318 (now US. Pat.No. 3,391,039).

It is therefore a primary object of the present invention to transportthe fabric along the support by a conveyor belt which substantiallyeliminates drive stresses in the fabric during the time the fabric isbeing formed and during the time the binder is setting-up.

In accordance with the present invention a conveyor belt is formed to atube shape as it moves toward the cylindrical support and the fabric iscarried on the conveyor belt, and is transported along the support,solely by the action of the conveyor belt. The conveyor belt isseparated from the fabric at the time the fabric is cut and changed fromthe tube form to a flat sheet. One or more drive rollers engage theconveyor belt after the belt and the fabric have been separated to pullthe belt without any contact between the drive rollers and the fabricitself.

As will be described in greater detail below, the con veyor belt is alsopreferably provided with a release medium which may be in the form of acoating or in the form of a separate film for insuring easy separationof the conveyor belt from the fabric.

Another important object of the present invention is to supply binder tothe magazine while the magazine is rotating so that the process does nothave to be stopped when the magazine runs low of binder. This object isachieved by connecting a ring for rotation with the magazine. The ringhas flanges at each end which extend radially in to provide a channel ortrough within the ring. The interior of the ring is connected to theinterior of the magazine. When liquid binder or adhesive is pumped intothis trough in the bottom part of the rotating ring, the centrifugalforce distributes the binder about the circumference of the ring andthrough the interconnecting conduit to the interior of the magazine.

Other and further objects of the present invention will be apparent fromthe following description and claims and are illustrated in theaccompanying drawings which, by-way of illustration, show preferredembodiments of the present invention and the principles thereof and whatare now considered to be the best modes contemplated for applying theseprinciples. Other embodiments of the invention embodying the same orequivalent principles may be used and structural changes may be made asdesired by those skilled in the art without departing from the presentinvention and the purview of the appended claims.

In the drawings:

FIG. 1 is a side elevation view of apparatus for forming nonwoven fabricconstructed in accordance with one embodiment of the present invention;

FIG. 2 is a fragmentary plan view of a guide arrangement for insuringaccurate positioning of the warp strands in the apparatus shown in FIG.1;

FIG. 3 is a fragmentary side elevation view of separator mechanism forseparating the conveyor belt from the fabric at the time the fabric iscut and opened from a tubular web to a fiat sheet;

FIG. 4 is an end elevation view taken along the line and in thedirection indicated by the arrows 4-4 in FIG. 3;

FIG. 5 is a fragmentary side elevation view showing details of themanner in which the conveyor belt is formed to a tube shape;

FIG. 6 is an end elevation view taken along the line and in thedirection indicated by the arrows 6-6 in FIG. 5;

FIG. 7 is an enlarged view of the conveyor belt drive arrangement of themachine shown in FIG. 1;

FIG. 8 is a fragmentary end elevation view of one form of outlet tipconstruction which can be used with a magazine of the apparatus shown inFIG. *1;

FIG. 9 is a side elevation view, in somewhat diagrammatic form, of anarrangement which can be used for maintaining a continuous feed ofbinder to the magazines of the apparatus shown in FIG. 1;

FIG. 10 is a fragmentary enlarged side elevation view, partly in crosssection, of a ring construction used for supplying binder to themagazine of the apparatus shown in FIG. 1;

FIG. 11 is a fragmentary side elevation view of a fill strand deliveryarrangement which incorporates an easily removable magazine;

FIG. 12 is a fragmentary end elevational view showing how the magazineof FIG. 11 may preferably be oriented to minimize stressing the fillstrand 'while achieving the desired positioning of binder on the fillstrand;

FIG. 13 is a fragmentary top plan view of the support showing how thesupport is formed with helically disposed slots for injecting air underpressure between the conveyor belt and the support; and

FIG. 14 is a fragmentary top plan view showing how canted guide rollersare mounted to alternately engage and release the side margins of thebelt to tighten the belt and to keep the belt from wandering sideways.

In FIG. 1 apparatus for forming nonwoven fabric constructed inaccordance with one embodiment of the present invention is indicatedgenerally by the reference numeral 21. The apparatus 21 is, as notedabove, of the general kind disclosed in detail in copending UnitedStates applications Ser. Nos. 281,421 filed May 20, 1963 (now US. Pat.No. 3,391,043) and 365,318 filed May 6, '1964 (now US. Pat. No.3,391,039) and assigned to the same assignee as the present invention.Reference is made to those applications for details of the parts of thestructure not described in detail below.

Briefly, the apparatus 21 includes One or more creel and tension carts(not shown in FIG. 1) for imparting a measured tension to a plurality ofwarp strands WS. The warp strands are lead through guide means, an eyeboard 22 and one or more reed guides 23 and 24, and through aconstricting ring 26 to the outer surface of a cylindrical support ormandrel 27.

One or more fill strand packages 28 are mounted on a drum 29, which isin turn mounted for rotation within a support 31 and is rotated by amotor 32. The fill strands F8 are led from the packages into a magazine33 which contains a liquid binder. The magazine is only partly filledwith the liquid binder, for reasons that will be described in detailbelow, and the fill strand is trained through the binder and thenthrough a binder metering and positioning tip 34. The outlet of the tip34 is located close to the support 27 and, because the warp strands arecontinuously moving along the support, the fill strand traces a helicalpath as it successively engages the warp strands during rotation of thedrum 29 about the warp strand.

The apparatus 21 preferably includes a heater, not visible in FIG. 1,for heating the binder to dry and set the binder while the engaged warpand fill strands are being carried along the support 27.

As thus far described the apparatus 21 and mode of operation arebasically like that disclosed in prior appli- 4 cation Ser. No. 365,318(now U.S. Pat. No. 3,391,039).

In the present invention the fabric is transported through the apparatus21 by a conveyor belt 36 rather than by any drive means which couldimpose stresses on the fabric tending to disrupt the bonds between thewarp and fill strands during the time these bonds are setting up.

As best shown in FIGS. 5 and 6, the conveyor belt is converted from aflat belt to a tube shape by a former 37 located in front of a support27. It is quite important that the belt be made to conform quite closelyto the surface of the cylindrical support 27, since any wrinkles wouldcause a corresponding disruption in the spacing of the strands of thefabric. The belt should be sufficiently resilient to stretch to shape,but it cannot be compressed without wrinkles. It is also quite importantthat there be no concavity in the upper surface of the belt since anyconcavity in that part of the belt would prevent the cylindrical supportfrom providing the desired support function. There is a natural tendencyof the belt to sag at the top during the time that it is being convertedfrom a flat belt to a tube shape and, in the process, is being flexed intwo directions. As illustrated in FIGS. 5 and 6 a roller 38 positionedin the manner illustrated provides effective support for the top part ofthe tube at this critical point in the formation of the tube. The rolleralso is a preferred means of support at this point because it minimizesdrag.

Before describing the drive arrangement for the conveyor belt in greaterdetail the manner in which the belt and the fabric are separated priorto cutting of the fabric will be reviewed. With reference to FIGS. 3 and4 it can be seen that the fabric F passes beneath a horizontallyextending plate 39 while the side edges of the belt 36 are forced up andare curled away from one another, see FIG. 4, by the combined action ofthe plate 39 and a plow shaped member 41 just prior to the time that acutter disc 42 cuts the fabric F along a line parallel to the warpstrand. The cutter disc 42 is rotated .by a hardened roll 43 whichengages the periphery of the disc and insures that the strands of thefabric passing between the roll 43 and the disc 42 are cleanly cut.

It is important that the edges of the belt 36 be separated to someextent at the time that the fabric is cut to avoid trimming portions offthe belt.

With particular reference now to FIG. 7, the conveyor belt 36 is pulledalong the support 27 by one or more drive rolls 46. A pressure roll 47maintains the belt 36 in driving contact with the drive roll 46. Thebelt 36 is an endless belt and returns to the inlet end of the support27 by passing over a series of positioning rollers 48.

The fabric F, after being cut by the cutter disc 42 is opened to a flatsheet and is wound upon a storage roll 49. The storage roll 49 is drivenby a separate motor, not shown, and the rotation of the storage roll 49is coordinated with the speed of the conveyor belt 36 to preventexcessive droop of the fabric F while avoiding stressing the fabric.This coordination is provided by a dancer roll 50. The coaction betweenthe dancer roll 50 and the drive for the storage roll 49 is the same asthat described for the corresponding elements in the above noted US.Pat. No. 3,391,039 at column 6, lines 723 of that patent. The storageroll 49 is driven by an electric motor under the controls of two mercurylevel switches which are not shown. The switches sense the level of thedancer roll 50 which indicates the amount of tension in the fabric.Normally one switch will be made to drive the storage roll, through arheostat control, at a selected take up speed. However, if this take upspeed should be too fast, the dancer roll 50 will be pulled upwardlyabout a pivotal mounting to energize the other switch which causes thestorage roll 49 to be driven at a slower speed, through a secondrheostat, until the fabric tension again decreases to the point wherethe storage roll 49 is driven by the energization of the first switch.Thus, the storage roll 49 is driven at a speed fast enough to preventany undue slack in the fabric, yet excessive tension which could causedistortion is at all times prevented.

The conveyor belt 36 is preferably made from a tough material of highdimensional stability. Mylar polyester film having a thickness between 7/2 and 10 mils has been found to be a quite satisfactory material forthe conveyor belt.

The conveyor belt may be coated with a release film which resistssticking of the binder or adhesive and thus facilitates separation ofthe belt from the fabric. Alternately, and as illustrated in FIG. 1, aseparate release film 51 may be employed. In this event the release film51 may be carried along the fabric F for some distance after the pointat which the belt 36 is separated from the fabric. Doing this lendsadditional support to the fabric F and provides more time for set up ofthe bonds between the warp and fill strands. The release film 51 is thenreturned to the conveyor belt 36 by passing the release film over aseries of rollers 52. A polypropylene film has been found to be a veryeffective release film.

It is important, as indicated above, that the conveyor belt (and releasefilm) be maintained free of wrinkles. To keep the belt tight in atransverse direction and to prevent depressions in the outer surface ofthe belt a series of guide rollers, inclined at an angle, alternatelyengage and release the belt 36. These canted guide -rolls 70 are shownin FIG. 14 of the drawings. These guide rollers grab and release theside margins of the belt and release film under the control of limitswitches to tighten the belt and to keep the belt from wanderingsideways.

The present invention also incorporates means for injecting air underpressure between the conveyor belt and the support 27. The air reducesfriction. This is especially important with high shrink fill strands.The support 27 is formed with slots 60, preferably helically disposed asshown in FIG. 13, to distribute the air about the support. Air pressuresof 2 to 50 p.s.i. have been found satisfactory.

As the fill strand engages the warp strand in the course of the rotationof the thread package and magazine about the support, the fill strandwill tend to pull each individual warp strand, at the moment ofengagement, sidewise to a limited extent in the direction of rotation ofthe rotating drum 29. The present invention uses this pulling tendencyto achieve precise lateral positioning of the warp strands.

The manner in which this is accomplished can best be explained byreference to FIG. 2.

FIG. 2 is a fragmentary plan view of the reed guide arrangement forestablishing the lateral position of the warp strands of the apparatusshown in FIG. '1. The dents 23D and 24D of the reed guides 23 and 24 arearranged in tandem relation, but instead of being arranged exactlycoincident, as viewed in the direction of movement of the warp strands,the dents 24D are offset slightly in a circumferential direction(downward as viewed in FIG. 2) so that the dents 24D are slightlylaterally offset in a direction opposed to the direction of rotation ofthe drum '29. As a result, the fill strand FS pulls each warp strand WSinto positive engagement with its associated dent 24D on the reed guide24 to thereby maintain precise and uniform spacing of the warp strands.While two reed guides have been illustrated as the guide elements forthe warp strands, the same principal can be utilized with other lateralguide elements. For example, the reed guide 24 could be used with theeyeboard 22 to achieve this same result.

As illustrated in FIG. 1 the warp strands pass through the interior of aconstricting ring 26 at the outlet of the reed guide 24. Thisconstricting ring insures that the warp strands are pulled down to thedesired radial position with respect to the surface of the support 27.An acetal molded resin ring, such as Delrin resin, has been found quitesatisfactory since it is both hard enough to resist wearing down of thesurface and yet smooth enough to avoid shredding of the warp strands.

The unstressed fabric transport provided by the conveyor belt makes itfeasible to use a binder which is a good film former but which mayprovide little or no tack or adhesion to the strands themselves. Thefill strand in passing through the magazine 33 is immersed in the liquidbinder, and as the fill strand passes out the tip 34, the tip wipes theadhesive off the top surface of the strand (as best illustrated in FIG.8) leaving sufficient adhesive on the underside of the strand to form afilleted film about substantially the entire diameter of each warpstrand at the area of engagement of the fill and warp strand. At thistime the location of the area of intersection of the warp and fillstrands is not at all dependent upon any action of the binder in holdingthe fill and warp strands together. The belt holds the engaged strandsin an absolute position until the film can form the strength to hold thestrands in engagement. Thus, the binder can be one which will formcohesive strength after set up and the binder need not be selected forany adhesive qualities. Since the binder forms a film over, under andall the way around the area of intersection, the joint is a highstrength joint after the film has set up.

The control of the amount of binder applied to the fill strand isdependent upon a combination of factors. It is dependent upon thecentrifugal force developed by rotation of the drum, the outlet diameterof the exit tip, the viscosity of the hinder, the immersion depth of themagazine, that is the length of thread that is immersed, and thewettability of the binder. In this last connection wetting agents can beadded to increase the wettability. There does not appear to be any reallimitation on the rotational speed. With the apparatus shown in FIG. 1the binder, in effect, is being moved past the fill strand. As a result,there is very little problem of throwing binder off of the fill strand.

When using a binder which is primarily a film former, that is, one thathas little initial adhesive properties, it is important to dry thefabric until the cohesive strength of the set up film is greater thanadhesion to the belt. This insures that the binder will pull clean fromthe belt and release medium and will avoid build up of binder on thebelt or on the release medium.

With the form of magazine and exit tip shown in FIG. 8 it has been founddesirable to use a bar 56, positioned as shown, to help turn the fillstrand FS rather than to rely entirely on contact of the fill strandwith the edge of the tip.

The present invention provides means for supplying binder to themagazine while the magazines are being rotated about the support. As aresult, it is not necessary to shut down to refill the magazines andmagazines of smaller capacity and resulting bulk and weight can be used.

FIG. 9 shows one form of apparatus for supplying binder to the magazineswhile the magazines are being rotated about the support. A pump 57 pumpsliquid binder from a reservoir 58 through a pipe 59 and into a trough orchannel formed within a ring 64. The ring 64 is mounted for rotation, bymeans not shown, with the magazines 33, and conduits 62 connect theinterior of the ring with the interior of the magazine. The centrifugalforce developed by the rotation of the ring 64 keeps the liquid binderin the radially outer portion of the ring and distributes the binderabout the circumference. Rotation at speeds as low as 25 to 30 rpm. willthrow the binder to the outside of the ring 61.

In some cases it is desirable to provide a continuous circulation ofbinder in the magazine 33. FIG. 9 shows one form of apparatus that canbe used to accomplish such circulation. The magazines 33 are connectedby conduits 66 with a second ring 67. The ring 67 is shaped to form acompletely enclosed interior except for the open annular area in thesurface facing the magazine needed for rotation of the conduit 66 withrespect to the ring. A metering orifice may be installed in the conduit66 to regulate the flow of binder through the conduit and rate at whichthe binder is circulated through the magazine. The binder, when itenters the ring 67, flows by gravity to the bottom of the ring and isreturned to the reservoir 58 by a pipe 68.

FIG. shows another form of ring arrangement for supplying binder to themagazine 33 while the magazine is rotating. In this case, the ring 64 isnestled within the ring 67 and is connected to the magazine by a conduit62. The binder is again placed in the trough 69 of the ring 64 at thebottom of the ring, in the manner shown in FIG. 9.

The ring 64 in the FIG. 10 form includes an overflow conduit 71,disposed radially inwardly of the conduit 62. When the binder level inthe magazine 33 comes up to the conduit 71 flow of binder into themagazine stops, and the excess binder in the ring 64 flows out theconduit 71 and into the return ring 67. The rings 64 and 67 may be madeof polypropylene since the binder, even when dry, does not readilyadhere to polypropylene.

As noted above, supplying the binder to the magazine while the magazineis rotating makes it feasible to use a relatively small and compactmagazine. In accordance with the present invention the magazine 33 mayalso be made separate from the fill strand supply means 28 (see FIG.11). As shown in FIG. 11 the magazine 33 may be made from tube stock andfitted with a pair of end caps 71.

The fill strand is led into the magazine through a ceramic eyelet 72 atthe liquid center of the magazine, and the warp strand is then passedthrough the binder B and out through the exit tube 34.

The inlet end of the exit tube 34 extends to the liquid center of themagazine 33 as illustrated in FIG. 11. The level of the liquid binder ismaintained below the liquid center so that the binder will be radiallybeyond the liquid center when the magazine is rotating and will beradially in from the eyelet 72 when the magazine is standing.

Only a portion of the mounting structure for the magazine 33 isillustrated in FIG. 11. The magazine 33 is detachably connected, as bystrap, to a plate 73. The plate 73 is connected by means not shown inFIG. 11 to the drum 29. The rotatable ring is also mounted on the plate73 by a strut 74. This mounting arrangement for the magazine 33 makes iteasy to remove and replace the magazine in the event of a malfunction.It also makes it easy to remove the magazine for cleaning, Since thetubular magazines illustrated in FIG. 11 can be relatively small andcompact (because of the provision for supplying liquid binder) asubstantial number of magazines can be mounted on the plate 73 to makerelatively high density and fill strand materials.

FIG. 12 illustrates a preferred orientation of the tubular magazines 33shown in FIG. 11. The axis of the magazine is angled as illustrated inFIG. 12 so that the magazine and the exit tube extend almost tangentialto the circumference of the cylindrical support 27. The inclination ofthe magazine is just enough below the tangent to produce the desiredwiping action of adhesive from the top of the fill strand leaving thetip of the exit tube.

While we have illustrated and described the preferred embodiments of ourinvention, it is to be understood that these are capable of variationand modification, and we therefore do not wish to be limited to theprecise details set forth, but desire to avail ourselves of such changesand alterations as fall within the purview of the following claims.

We claim:

1. Apparatus for making nonwoven fabric and comprisa support,

warp strand guide means for guiding a plurality of warp strandscontinuously in a longitudinal direction over the support,

fill strand means rotatable about the warp strands for engaging a fillstrand under tension with the warp strands supported on the supportwhile applying a binder to bond the warp and fill strands together, and

drive means for transporting the warp strands and nonwoven fabric alongthe support without stressing the fabric, said drive means comprising adrive roller and a conveyor belt interposed between the warp strands andthe support and effective to transport the fabric by the frictiondeveloped bet-ween the belt and the fabric and the drive roller whichengages the belt but does not contact the fabric.

2. Apparatus as defined in claim 1 including a release film between theconveyor belt and the fabric for preventing contact of the binder withthe belt.

3. Apparatus as defined in claim 2 wherein the belt is polyester filmand the release film is polypropylene film.

4. Apparatus as defined in claim 1 including guide rollers engageablewith the belt at an angle and effective to keep the belt tight in atransverse direction.

5. Apparatus as defined in claim 1 including means for injectingpressurized air between the support and the belt to reduce frictionbetween the belt and support.

6. Apparatus as defined in claim 1 wherein the support is a horizontalcylindrical member, the warp strand guide means form the warp strandsinto a cylindrical bundle about the support, and including shaping meansfor shaping the belt to a tube about the support with the side edges ofthe belt on the underside of the support, said shaping means including amember which engages the inside of the top of the tube in front of thesupport to press that part of the tube radially out and to therebyinsure that there are no concavities in the upper surface of the tube.

7. Apparatus for making nonwoven fabric and comprising,

a support,

warp strand guide means for guiding a plurality of warp strandscontinuously in a longitudinal direction over the support, fill strandmeans rotatable about the warp strands for engaging a fill strand undertension with the warp strands supported on the support while applying abinder to bond the warp and fill strands together, and

drive means for transporting the warp strands and fabric along thesupport,

said warp strand guide means including two guide elements arranged intandem with the second guide element nearest the support slightlylaterally offset with respect to the other guide element in a directionopposed to the direction of movement of rotation of the fill strand sothat each warp strand is pulled into positive engagement with itsassociated second guide element by the force exerted by the fill strandat the area of engagement with the warp strand to thereby maintainprecise spacing of the warp strands.

8. Apparatus as defined in claim 7 wherein the support is cylindricaland wherein the warp strand guide means form the warp strands into acylindrical bundle at the outlet of the tandem guide elements andincluding an acetal molded resin ring between the guide elements and thesupport for constricting the bundle of warp strands between the guideelement and the support.

9. Apparatus for continuously producing nonwoven fabric of indeterminatelength comprising, warp strand means for moving a plurality of warpstrands in a longitudinal, horizontal direction under a controlledtension, positioning means for positioning the warp strands in a fixedlateral and vertical position, fill strand means rotatable in an annularpath about the horizontally moving warp strands for laying a fill strandon the warp strands in a helix during longitudinal movement of the warpstrands, a magazine containing a binder mounted on the fill strand meansand rotatable with the fill strand means in said annular path about thehorizontally moving Warp strands, said magazine having entrance and exitmeans for introducing the fill strand into the binder in the magazine asthe fill strand passes through the magazine, stationary strand supportmeans for supporting the engaged Warp and fill strands and binder supplymeans for supplying binder to the magazine while the magazine isrotating, said supply means comprising a ring concentric With the axisof rotation of the magazine and formed with radially extending flangesat each end to provide a trough within the ring, means mounting the ringfor rotation with the magazine, a conduit connecting the trough in thering with the magazine, and means for putting binder in the trough Whilethe ring is rotating at a speed fast enough to keep the binder in thetrough by centrifugal action.

10. Apparatus as defined in claim 9 including a second stationary ringencircling the rotatable ring and having a trough for receiving excessbinder from the rotatable ring.

11. Apparatus as defined in claim 9 wherein the fill strand meansinclude a rotatable drum and a fill strand 10 package supply meansmounted on the drum, a carrier for the rotatable ring and supportsconnecting the carrier to the drum and wherein the magazine isdetachably mounted on the carrier without any connection to the fillstrand package supply means so that the magazine can be readily removedand replaced 12. Apparatus as defined in claim 9 wherein the Warp strandmeans include a conveyor belt interposed between the Warp strands andthe support and drive means which engage the belt but which do notengage the fabric whereby the fabric is transported along the support bythe friction between the belt and the fabric is not stressed by thedrive means.

No references cited.

BENJAMIN A. BORCHELT, Primary Examiner T. H. WEBB, Assistant ExaminerUS. Cl. XR. 156-426, 429, 171

